Hi! I am running my own business. I want a favor from you all. My issue is that one of my clients hasn’t made his payment since last four months and I am having his phone number only. I have searched for his address but was not able to find it anywhere as I think it is an unlisted number. But I really want back my money. Is there any hope to recover his full information?
Any help is appreciated.

what country is the client located in?

and what method did they use to pay you previously?

Shouldn't you contract services from a collection agency?
What kind of business do you have? Do you have some kind of a signed contract? An invoice?
How did they pay you in the past? Can't your bank help you (if they transferred the payment to your account. Otherwise, you would have had to meet them for them to make payments, right?)
If your only means of contacting your client was via telephone (ie you didn't have their address, email address, etc.), I believe it is rather difficult to get that kind of information. The police might think you are stalking the person or just want to find out where someone lives.

You also say you want your money BACK. Did you loan this person money? If so, why do you only have a telephone number?

Oh! Not to worry. One of my friend who is also a business man had also faced the same circumstances but he came across unlisted phone numbers which assisted him to retrieve the particular number’s information. Now he usually takes help of this service. I think you should also try this.
All the best.

from mod - this message includes a link to a pay website. Lets be careful.

That is not a free site (it's a link to one of those God awful "pay for the pleasure of searching the web for you" sites). I tried it to test my mother's home number (which is unlisted; she's a DA) and nothing came up so I'm not sure it works very well. Their own "PR" on the website claims a rather high success rate but of course it would (they are trying to sell you something). It also does not work on non-US numbers.

Again, could you contact your bank for details if they have paid you in the past using a bank account? Use the same method you used when contacting them to loan them money/provide services.

Your profile says that you are in the United States so I assume this person is in the Netherlands (otherwise you would just contact an American collection agency or try measures there). I'm afraid you're out of luck (my husband works for CGB but when I mentioned it to him, he said it sounds sketchy*). He said something about you should go to a company like Intrum Justitia but otherwise it's pretty hard to collect debts for the US in the Netherlands (not impossible but difficult).
*Take this with a big grain of salt because as much as I love my husband, he tends to think he knows everything. His male chromosomes tend to take over when I ask about legal matters . :-)

its a new form of spam where the topic starter bot posts a question, off topic to the forum, and the responder bot registers a day or so later and posts a response with a link. this is not the first one on this forum.